1. Field of the Invention
The invention relates to apparatus for preventing an uncontrolled emission of gaseous hydrocarbons during the filling of containers, particularly tank wagons or fuel tankers, with mineral oil products. It has a filling pipe around which is arranged a jacket tube whose outside diameter is smaller than the opening of the filling aperture of the container. The jacket tube defines an annular space between it and the filling pipe. The apparatus has an elastic packing between the outer wall of the jacket tube and the inner wall of the filling aperture.
2. Description of the Prior Art
The filling of a tank wagon normally takes place through a manhole which is at the top of the tank. Mineral oil products flowing in thereby displace the evaporated parts of the loaded product which is in the interior of the tank, and these evaporated constitutents emerge through the manhole and accumulate in the vicinity of the filling station. Apart from a not inconsiderable loss of the product, these quantities of hydrocarbon vapor case pollution of the environment. Heretofore, it has been proposed to use apparatus for preventing an uncontrolled emission or escape of gaseous hydrocarbons during the filling of containers, particularly tank wagons, with mineral oil products, which apparatus was characterised in that around a filling pipe there was arranged a jacket tube whose outside diameter was smaller than the opening of the filling aperture of the container. It defined an annular space between the filling pipe and the jacket tube. At the upper end of the annular space, an annular duct was provided which was sealed in relation to the filling pipe and had a suction pipe for the emerging gaseous hydrocarbons. And, it had an elastic packing arranged between the outer wall of the jacket tube and the inner wall of the filling aperture.
In practical loading operations it has, however, been found that the gas suction pipe which ran from the annular duct which was fastened to the jacket tube, was subject to disturbance. This was because for the sake of necessary mobility, it was constructed as a telescopic tube whose tolerances were very small in order to provide the necessary gas tightness. Therefore, damage easily occured during rough loading conditions. Jamming and leaks were the result.
A further disadvantage of the known apparatus consisted in that the design of the elastic packing was unequal to the high mechanical stresses occurring when the filling pipe was introduced into the manhole or the like. As tank wagons must be regarded not only from the point of view of their very variable structural shapes but also from their manufacture as coarse machine constructions, so variations in dimensions may be quite considerable. Thus, it has not always been possible to span these variations with known inflatable elastic packings. Or, least, these dimensional variations have led to high lateral stresses on the packing.
According to British Patent Specification No. 1 287 872, a filling apparatus is known which provides for the displaced vapors being drawn off through an annular space that is defined between the outer wall of the filling pipe and the inner wall of the jacket tube. It has the outer wall of the jacket tube sealed in relation to the inner wall of the manhole of the container to be filled, by having an inflatable annular beading. However, such apparatus has the disadvantage that the filling pipe or tube is not slidingly fixed in the jacket tube. Consequently, the filling pipe, when it is dipped into the tank or container which has to be filled, cannot adapt itself to the various tank dimensions so as to allow the filling pipe to rest upon the floor of the tank during the filling operation. Thus, the liquid which is being fed into the tank flows in from a relatively great height and gives rise to an electrostatic charge which may create a dangerous electrostatic potential between the fluid and tank wall.
Some old U.S. patents have dealt with the filling of beer kegs, etc., using fill tubes and having annular connection at the bunghole. However, the structures deal with maintaining pressure on the beer and they are quite complex.
Consequently, it is an object of this invention to provide apparatus of the type mentioned above, which is equal to the stresses occurring in an automatic loading operation, and which overcomes the aforementioned disadvantages.